In this paper, a performance analysis of millimeter wave (mmWave) massive multiuser multiple input and multiple output (MU-MIMO) channel within an underground mine is performed. The analysis is based on channel measurements conducted at 28 GHz using a base station of 64 virtual antenna elements serving multiple users. Channel characteristics such as large-scale path loss, time dispersion, coherence bandwidth and sum-rate capacity are reported and evaluated. The results indicate that multi-slope path loss model is better suited for precise prediction of path loss across various propagation segments within the mining gallery. The time dispersion analysis reveals that the underground mine channel does not cause significant time dispersion, as 90% of the root-mean-square (RMS) delay spreads are below 4 ns. In addition, it was found that the RMS delay spread is not dependent on the propagation distance. The study on sumrate capacity highlights the potential of employing massive MIMO technology to improve the channel's spectral efficiency. The analysis reveals that the capacity, with eight active users, can reach up to 33.54 bit/s/Hz. The outcomes of this paper offer valuable insights into the propagation properties of underground mine environment, which is characterized by rich-scattering and irregular topology.